WO2022142101A1 - High-toughness and high-aging impact steel plate and manufacturing method therefor - Google Patents

Abstract

Disclosed are a high-toughness and high-aging impact steel plate and a manufacturing method therefor, and the present invention relates to the technical field of steel production. The high-toughness and high-aging impact steel plate comprises the following chemical components by mass percent: 0.12-0.22% of C, 0.10-0.60% of Si, 1.15-1.60% of Mn, less than 0.020% of P, less than 0.015% of S, with the following one or more alloy elements being added: 0-0.060% of Nb, 0-0.12% of Ti and 0.010-0.050% of Al, with the balance being iron and inevitable impurity elements. The steel plate can withstand and resist complex marine stress at a low temperature of -40°C, the lowest yield strength thereof is 345 MPa, same has good toughness at a low temperature of -40°C, excellent aging performance, and also has good welding performance and a low carbon equivalent.

Description

A kind of high toughness and high aging impact steel plate and its manufacturing method technical field

The invention relates to the technical field of iron and steel production, in particular to a high-toughness and high-aging impact steel plate and a manufacturing method thereof.

Background technique

It is predicted that the international market needs about 3.5 to 4.6 million tons of marine steel every year. The utilization and development of marine resources is in the ascendant. The demand for structural steel in marine engineering is increasing year by year, and the market prospect is promising. Countries in the Middle East often demand high toughness and high aging impact toughness steel plates for the manufacture of offshore engineering structures and oil and gas platforms. Therefore, developing and supplying high-toughness and high-aging impact steel plates and opening up the international market is conducive to competing for international market share with steel mill giants such as Japan, Europe, America, and South Korea.

SUMMARY OF THE INVENTION

In view of the above technical problems, the present invention overcomes the shortcomings of the prior art, and provides a high-toughness and high-aging impact steel plate, whose chemical composition and mass percentage are as follows: C: 0.12% to 0.22%, Si: 0.10% to 0.60%, Mn: 1.15%～1.60%, P<0.020%, S<0.015%,

One or more of the following alloying elements are added: Nb: 0%-0.060%, Ti: 0%-0.12%, Al: 0.010%-0.050%, and the balance is iron and inevitable impurity elements.

The technical scheme that the present invention is further limited is:

The chemical composition and mass percentage of the aforementioned high toughness and high aging impact steel sheet are as follows: C: 0.16%, Si: 0.29%, Mn: 1.58%, P: 0.011%, S: 0.002%, Nb: 0.036% , Ti: 0.015%, Al: 0.026%, the remainder is iron and inevitable impurity elements.

The chemical composition and mass percentage of the aforementioned high-toughness and high-aging impact steel sheet are as follows: C: 0.17%, Si: 0.26%, Mn: 1.55%, P: 0.012%, S: 0.002%, Nb: 0.026% , Ti: 0.017%, Al: 0.032%, the balance is iron and inevitable impurity elements.

The chemical composition and mass percentage of the aforementioned high toughness and high aging impact steel sheet are as follows: C: 0.16%, Si: 0.29%, Mn: 1.56%, P: 0.011%, S: 0.001%, Nb: 0.027% , Ti: 0.019%, Al: 0.025%, and the balance is iron and inevitable impurity elements.

The chemical composition and mass percentage of the aforementioned high toughness and high aging impact steel sheet are as follows: C: 0.13%, Si: 0.23%, Mn: 1.53%, P: 0.013%, S: 0.001%, Nb: 0.019% , Al: 0.030%, the remainder is iron and inevitable impurity elements.

The aforementioned high-toughness and high-aging impact steel plate has a thickness of 6-80 mm, and the structure of the steel plate is a uniform and fine ferrite-pearlite structure.

Another object of the present invention is to provide a method for manufacturing a high-toughness and high-aging impact steel plate, which specifically includes the following steps:

Hot metal pretreatment S < 0.010%; after BOF smelting furnace, deoxidation alloying is more than 90%; LF refining outside the furnace for 15-30 minutes, fine-tuning alloy composition and molten steel temperature; RH vacuum degassing treatment for 15-30 minutes, RH bottom blowing Argon is stirred reasonably and floated to remove non-metallic inclusions to reduce the content of nitrogen, hydrogen and oxygen; calcium wire is fed to purify molten steel to spheroidize non-metallic inclusions; the whole process of argon protection is poured, the pulling speed is 0.75-1.3m/min, and electromagnetic stirring;

The slab is then uniformly heated at 1100～1220℃, and the heating time is 3.5～4.5 hours;

Four-high reversing rolling mill two-stage rolling, rolling reduction ratio is greater than 60%, rough rolling temperature is 1070-1180 °C, second-stage rolling temperature is 890-950 °C, and final rolling temperature is 800-880 °C;

Controlled cooling, the temperature of the steel plate returning to red is 600-690 °C;

Nine-roll straightening machine straightening 3～6mm/m;

Finished product identification and inspection; qualified warehousing and delivery.

The beneficial effects of the present invention are:

(1) The present invention has developed a new type of pure steel, which is mainly used in the manufacture of offshore engineering structures, which can withstand the complex stress of the ocean at a low temperature of -40°C, with a minimum yield strength of 345MPa and a low temperature -40°C toughness. Good, excellent aging performance, good welding performance, low carbon equivalent;

(2) In the present invention, the composition is designed to be low-carbon microalloying, and refining is carried out to remove inclusions, nitrogen and hydrogen gases are removed, and uniform and fine microstructures are obtained, and high low temperature toughness and strain aging impact toughness are obtained, especially -40°C low temperature. Impact toughness and 5% strain aging impact performance, uniform structure and superior performance;

(3) The present invention is mainly used as an export material, promotes the manufacture of offshore engineering structures, ensures the construction, installation and operation safety of offshore engineering structures. efficiency;

(4) The present invention is conducive to promoting the upgrading of metallurgical products and marine structural products in my country, promoting the quality improvement of marine steel products with a large amount of applications and a wide range of applications, and promoting the exploitation and utilization of seabed resources, and has broad prospects for quality and benefit development.

Detailed ways

Example 1

This embodiment provides an 80mm specification API 2H-50 steel sheet, whose chemical composition and mass percentage are as follows: C: 0.16%, Si: 0.29%, Mn: 1.58%, P: 0.011%, S: 0.002%, Nb: 0.036 %, Ti: 0.015%, Al: 0.026%, and the balance is iron and inevitable impurity elements.

The manufacturing method thereof specifically includes the following steps:

Hot metal pretreatment S < 0.010%; after BOF smelting furnace, deoxidation alloying is more than 90%; LF refining outside the furnace for 25 minutes, fine-tuning the alloy composition and molten steel temperature; RH vacuum degassing for 25 minutes, RH bottom blowing argon with reasonable stirring and Float to remove non-metallic inclusions and reduce the content of nitrogen, hydrogen and oxygen; feed calcium wire to purify molten steel to spheroidize non-metallic inclusions; pour under argon protection throughout the process, pulling speed 0.95m/min, electromagnetic stirring;

The slab is then uniformly heated to 1180°C for 4.5 hours;

Four-high reversing rolling mill two-stage rolling, rolling reduction rate of 62%, rough rolling temperature of 1180 °C, second-stage rolling temperature of 890 °C, and final rolling temperature of 810 °C;

Controlled cooling, the temperature of the steel plate returning to red is 620℃;

Nine-roll straightening machine straightening 6mm/m;

Finished product identification and inspection; qualified warehousing and delivery.

The mechanical properties of the steel plate were obtained: the yield strength was 380MPa, the tensile strength was 520MPa, and the elongation was 26%. -40℃, V-shaped impact energy 216J, 220J, 212J (10*10mm). -40℃, 5% deformation aging impact toughness is 136J, 131J, 143J (10*10mm).

Example 2

This embodiment provides a 50mm specification API 2H-50 steel sheet, whose chemical composition and mass percentage are as follows: C: 0.17%, Si: 0.26%, Mn: 1.55%, P: 0.012%, S: 0.002%, Nb: 0.026 %, Ti: 0.017%, Al: 0.032%, and the balance is iron and inevitable impurity elements.

The manufacturing method thereof specifically includes the following steps:

Hot metal pretreatment S < 0.010%; after BOF smelting furnace, deoxidation alloying is more than 90%; LF refining outside the furnace for 25 minutes, fine-tuning the alloy composition and molten steel temperature; RH vacuum degassing for 25 minutes, RH bottom blowing argon with reasonable stirring and Float to remove non-metallic inclusions and reduce the content of nitrogen, hydrogen and oxygen; feed calcium wire to purify molten steel, spheroidize non-metallic inclusions; pour under argon protection throughout the process, pulling speed 0.95m/min, electromagnetic stirring;

The slab is then uniformly heated to 1170°C, and the heating time is 4.4 hours;

Four-high reversible rolling mill two-stage rolling, rolling reduction rate of 62%, rough rolling temperature of 1130 °C, second-stage rolling temperature of 900 °C, and final rolling temperature of 830 °C;

Controlled cooling, the temperature of the steel plate returning to red is 630 °C;

Nine-roll straightening machine straightening 5.6mm/m;

Finished product identification and inspection; qualified warehousing and delivery.

The mechanical properties of the steel plate were obtained: the yield strength was 400 MPa, the tensile strength was 510 MPa, and the elongation was 22%. -40℃, V-shaped impact energy 196J, 195J, 213J (10*10mm). -40℃, 5% deformation aging impact toughness is 155J, 149J, 151J (10*10mm).

Example 3

This embodiment provides a 20mm specification API 2H-50 steel sheet, whose chemical composition and mass percentage are as follows: C: 0.16%, Si: 0.29%, Mn: 1.56%, P: 0.011%, S: 0.001%, Nb: 0.027 %, Ti: 0.019%, Al: 0.025%, and the balance is iron and inevitable impurity elements.

The manufacturing method thereof specifically includes the following steps:

Hot metal pretreatment S < 0.010%; after BOF smelting furnace, deoxidation alloying is more than 90%; LF refining outside the furnace for 26 minutes, fine-tuning the alloy composition and molten steel temperature; RH vacuum degassing for 25 minutes, RH bottom blowing argon with reasonable stirring and Float to remove non-metallic inclusions and reduce the content of nitrogen, hydrogen and oxygen; feed calcium wire to purify molten steel and spheroidize non-metallic inclusions; pour under argon protection throughout the process, pulling speed 0.90m/min, electromagnetic stirring;

The slab is then uniformly heated to 1190°C for 4.5 hours;

Two-stage rolling with four-high reversing mill, rolling reduction rate of 62%, rough rolling temperature of 1150 °C, second-stage rolling temperature of 910 °C, and final rolling temperature of 825 °C;

Controlled cooling, the temperature of the steel plate returning to red is 630 °C;

Nine-roll straightening machine straightening 5mm/m;

Finished product identification and inspection; qualified warehousing and delivery.

The mechanical properties of the steel plate were obtained: the yield strength was 415MPa, the tensile strength was 535MPa, and the elongation was 25%. -40℃, V-shaped impact energy 177J, 182J, 177J (10*10mm). -40℃, 5% deformation aging impact toughness is 113J, 122J, 123J (10*10mm).

Example 4

This embodiment provides a 6mm specification API 2H-50 steel sheet, whose chemical composition and mass percentage are as follows: C: 0.13%, Si: 0.23%, Mn: 1.53%, P: 0.013%, S: 0.001%, Nb: 0.019 %, Al: 0.030%, the balance is iron and inevitable impurity elements.

The manufacturing method thereof specifically includes the following steps:

Hot metal pretreatment S < 0.010%; after BOF smelting furnace, deoxidation alloying is more than 90%; LF refining outside the furnace for 25 minutes, fine-tuning the alloy composition and molten steel temperature; RH vacuum degassing for 25 minutes, RH bottom blowing argon with reasonable stirring and Float to remove non-metallic inclusions and reduce the content of nitrogen, hydrogen and oxygen; feed calcium wire to purify molten steel to spheroidize non-metallic inclusions; pour under argon protection throughout the process, pulling speed 0.95m/min, electromagnetic stirring;

The slab is then uniformly heated to 1190°C, and the heating time is 4.2 hours;

Four-high reversible rolling mill two-stage rolling, rolling reduction rate of 65%, rough rolling temperature of 1150 °C, second-stage rolling temperature of 930 °C, and final rolling temperature of 880 °C;

Controlled cooling, the temperature of the steel plate returning to red is 620℃;

Nine-roll straightening machine straightening 56mm/m;

Finished product identification and inspection; qualified warehousing and delivery.

The mechanical properties of the steel plate were obtained: the yield strength was 375MPa, the tensile strength was 515MPa, and the elongation was 22%. -40℃, V-shaped impact energy 88J, 92J, 93J (5*10mm). -40℃, 5% deformation aging impact toughness is 75J, 81J, 73J (5*10mm).

To sum up, the present invention has developed a new material of high toughness, high aging impact toughness, low alloy steel for offshore oil and gas production offshore platforms and a manufacturing method thereof, which meets the needs of the international market, and has good low temperature toughness and Strain-aged impact toughness properties. According to the annual production and sales volume of 100,000 to 200,000 tons, and the gross profit per ton of steel is 360 yuan, the annual gross profit exceeds 36 million to 72 million yuan, which is conducive to promoting steel exports, developing the Middle East and other marine structural steel markets, winning international reputation, and having huge potential social benefits. .

In addition to the above-described embodiments, the present invention may also have other embodiments. All technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims (7)

1. A high-toughness and high-aging impact steel plate is characterized in that: its chemical composition and mass percentage are as follows: C: 0.12%-0.22%, Si: 0.10%-0.60%, Mn: 1.15%-1.60%, P<0.020%, S < 0.015%,

   One or more of the following alloying elements are added: Nb: 0%-0.060%, Ti: 0%-0.12%, Al: 0.010%-0.050%, and the balance is iron and inevitable impurity elements.
2. A high-toughness and high-aging impact steel plate according to claim 1, characterized in that: its chemical composition and mass percentage are as follows: C: 0.16%, Si: 0.29%, Mn: 1.58%, P: 0.011%, S: 0.002%, Nb: 0.036%, Ti: 0.015%, Al: 0.026%, and the balance is iron and inevitable impurity elements.
3. A high-toughness and high-aging impact steel plate according to claim 1, characterized in that: its chemical composition and mass percentage are as follows: C: 0.17%, Si: 0.26%, Mn: 1.55%, P: 0.012%, S: 0.002%, Nb: 0.026%, Ti: 0.017%, Al: 0.032%, and the balance is iron and inevitable impurity elements.
4. A high-toughness and high-aging impact steel plate according to claim 1, characterized in that its chemical composition and mass percentage are as follows: C: 0.16%, Si: 0.29%, Mn: 1.56%, P: 0.011%, S: 0.001%, Nb: 0.027%, Ti: 0.019%, Al: 0.025%, and the balance is iron and inevitable impurity elements.
5. A high-toughness and high-aging impact steel plate according to claim 1, characterized in that: its chemical composition and mass percentage are as follows: C: 0.13%, Si: 0.23%, Mn: 1.53%, P: 0.013%, S: 0.001%, Nb: 0.019%, Al: 0.030%, and the balance is iron and inevitable impurity elements.
6. A high-toughness and high-aging impact steel plate according to claim 1, characterized in that: the thickness of the steel plate is 6-80 mm, and the structure of the steel plate is a uniform and fine ferrite-pearlite structure.
7. A method for manufacturing a high-toughness and high-aging impact steel plate, characterized in that: applied to any one of claims 1-6, and specifically comprising the following steps:

   Hot metal pretreatment S < 0.010%; after BOF smelting furnace, deoxidation alloying is more than 90%; LF refining outside the furnace for 15-30 minutes, fine-tuning alloy composition and molten steel temperature; RH vacuum degassing treatment for 15-30 minutes, RH bottom blowing Argon is stirred reasonably and floated to remove non-metallic inclusions to reduce the content of nitrogen, hydrogen and oxygen; calcium wire is fed to purify molten steel to spheroidize non-metallic inclusions; the whole process of argon protection is poured, the pulling speed is 0.75-1.3m/min, and electromagnetic stirring;

   The slab is then uniformly heated at 1100～1220℃, and the heating time is 3.5～4.5 hours;

   Four-high reversing rolling mill two-stage rolling, rolling reduction ratio is greater than 60%, rough rolling temperature is 1070-1180 °C, second-stage rolling temperature is 890-950 °C, and final rolling temperature is 800-880 °C;

   Controlled cooling, the temperature of the steel plate returning to red is 600-690 °C;

   Nine-roll straightening machine straightening 3～6mm/m;

   Finished product identification and inspection; qualified warehousing and delivery.